Schematic representation of interactions between Bcl-2 family members as reported in current literature. The literature on interactions between all human and mouse Bcl-2 family members (supplemental Table 1) was reviewed as outlined in supplemental “Materials and methods.” Reported interactions were categorized according to the methodology (M) used to assess the interaction, as indicated by the numbers in the right-hand column. Categories were (1) affinity measurements in vitro, using BH3-domain peptides and isolated, C-terminally truncated prosurvival Bcl-2 proteins; (2) immunoprecipitations from cells expressing exogenous Bcl-2 family proteins; (3) immunoprecipitations from cells expressing endogenous Bcl-2 family proteins; and (4) nuclear magnetic resonance and crystal structures with recombinant proteins or biophysical measurements of interaction between full-length proteins. Boxes are color-coded for the Bcl-2 family protein pairs in each category according to the reported strength of their interaction. The number in each box refers to the pertinent publication, as cited in supplemental Table 1.